FAA Certifies Sikorsky’s Auto Rig Approach for S-92

Offshore operator PHI worked with Sikorsky to design an automated rig approach for the S-92 to reduce pilot workload by eliminating manual flying in the intermediate stages of the approach.

The FAA has certified a new functionality on the Sikorsky S-92: an automated rig approach for offshore operators intended to decrease workload when the crew is in a critical flight phase. Sikorsky intends eventually to bring the same capability to the smaller S-76D.

The S-92’s autopilot already had a search-and-rescue (SAR) mode that could fly the rotorcraft to a point in space. Sikorsky design engineers, collaborating with operator PHI, built on this mode to create the new functionality. In addition, the weather radar ensures the flight path is free from obstacles.

“You eliminate manual flying in intermediate stages such as the initial approach fix, final approach fix and descent to the final decision point,” Dan Hunter, director of commercial programs, told AIN.

As a result, the workload is reduced to seven pilot-initiated items from 17. The system can fly the helicopter to a target offset point 0.5 nm from the rig, and Sikorsky hopes to reduce this distance further. “Our goal is 200 feet ceiling with quarter-nm visibility; the system is capable of this, and we are working on the certification,” Sikorsky project pilot Ron Doeppner said.

The automated rig approach system incorporates inputs from the flight management system, the GPS and the radar altimeter and factors in wind conditions at the rig. Hunter said SAR mode installation is not a prerequisite for the rig approach system. Also, if an aircraft is already equipped with the SAR mode, it may need upgraded hardware and software.

Doeppner explained that “it will take the pilot approximately 20 seconds to build the approach.” He has to enter four variables: the destination waypoint (the rig coordinates), the inbound course (into the wind), the minimum descent height (50 feet above the landing platform) and the offset direction (left or right) and distance. “Those steps can be accomplished at any time but usually 20 to 50 miles from the rig,” Doeppner said. Once the approach is built, the pilot presses a single button and the aircraft automatically flies the approach.

Either pilot can set up the approach. On final approach, the landing pilot (right seat for a left offset and left seat for a right offset) will have his eyes outside the aircraft looking for the rig. The non-flying pilot will have his eyes inside the aircraft monitoring the approach. One day of simulator training should be sufficient, according to Doeppner.

The bottom line, Sikorsky officials believe, will be safer operations under challenging weather and operating conditions. In addition, Sikorsky hopes that the system’s “intuitive interface” will reduce the potential for controlled flight into terrain (CFIT).

Certification, not technology, was the trickier part of the job. “We spent one year developing the rig approach functionality but it took us a year-and-a-half to convince the authorities,” Hunter said. “Automated rig approach had never been done before, so the FAA had no basis on which to compare it,” Doeppner added.

The system will be available as an option and can be retrofitted to aircraft already in service. Hunter declined to disclose the price, saying only that it is six digits in U.S. dollars. Some 170 S-92s are flying worldwide.

“We have every intention of installing it on the S-76D,” Hunter added. It would be on only the latest version of the 12-seater, however. The avionics architecture on earlier variants, such as the S-76C, would make a retrofit too difficult.